Composite materials used in the transport industry and also in other sectors must have a certain degree of flame resistance. For this purpose, commonly used flame retardants are based on halogen compounds in the liquid state or aluminum hydroxide in the solid state. Solid flame retardants have a negative effect on the processing and mechanical properties. Low viscosity and rapid wettability of fibers are very important, especially in an resin transfer molding (RTM) process. Therefore, a new advanced matrix system based on phosphorus flame retardants was developed. The flame resistance and mechanical properties of the composite materials produced from the new resin system were tested. Furthermore, the processing parameters and tests are described in the article.